Growth hormone (GH) secretion is decreased in obese subjects. Purpose is to determine whether weight loss induced by bariatric surgery will increase spontaneous pulsatile GH secretion as well as the response to the synthetic hexapeptide GH releasing-peptide (GHRP) in morbidly obese patients. Changes in GH secretion will be correlated with changes in the resting metabolic rate, body composition, maximal oxygen consumption, sleep patterns and several other hormones.